It's not bad idea but it should be systematic and well planned, I see my failure at doing the selling 5% of my whole BTC, if i will not do it systematically and continuously, and you should do this when bitcoin's price is rising and not on the time when the price is playing see saw.
I guess the price has risen to cross the 7k mark after a dump due to all that BCH crap news and thus I would be skeptical to sell at this point. Another dump may occur soon. I think I am happy to hold my coins for now and wait for bitcoin to rise beyond the 8k mark. I am keeping 5% for selling once it crosses that.
I live by the method of getting your original investment back and playing with the "banks" money. You can sleep easy if you do this.
I guess you mean to say that you are reinvesting the profit that you gain from selling bitcoin when prices have risen and you have sold? Well for some people even that will not give then proper sleep if you ask me.